JP2018158350A - Laser welding method and welded joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser welding method and a welded joint capable of homogeneously forming a weld bead shape by fillet welding.SOLUTION: A laser welding method includes: a first weld bead formation step of forming a first weld bead B1 along a planned welding line L on a corner 11 formed of an end face 6a of an outer plate 2 and a vehicle outside surface 4a of an entrance frame 3; a second weld bead formation step of forming a second weld bead B2 along a planned weld line L on a corner 12 positioned on an opposite side to the corner 11 out of corners constituting the end face 6a of the outer plate 2; and a third weld bead formation step of forming a third weld bead B3 along a planned scheduled line L on the end face 6a of the outer plate 2, where the first to third weld beads B1 to B3 formed by the first to third weld bead formation steps are connected to each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laser welding method and a welded joint.

  Fillet welding is known as a form of laser welding. For example, in the field of railway vehicle structures, the edge of the entrance / exit frame is overlapped with the edge of the outer plate 2, and the overlapped portion is fillet welded with a laser to ensure water tightness of the vehicle (for example, patents) Reference 1).

JP 2007-112343 A

  In the fillet welding as described above, the homogeneity of the weld bead shape formed in the welded portion is required from the viewpoint of ensuring the strength and aesthetics of the welded portion.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a laser welding method and a welded joint capable of forming a weld bead shape uniformly in fillet welding.

  In the laser welding method according to one aspect of the present invention, the end face of one workpiece and the one surface of the other workpiece are fillet welded along a planned welding line set at an overlapping portion of the plate-like workpieces. A first welding bead forming step of forming a first weld bead along a planned welding line at a corner formed by an end surface of one workpiece and one surface of the other workpiece; A second weld bead forming step of forming a second weld bead along a planned welding line at a corner located on the opposite side of the corner from among the corners constituting the end surface of the one workpiece; And a third weld bead forming step for forming a third weld bead along the planned weld line on the end face of the first to third welds formed in the first to third weld bead forming steps Connect the beads together.

  In this laser welding method, the first to third weld beads formed in the first to third weld bead forming steps are connected to each other. Thereby, the welding bead formed over the corner | angular part of a workpiece | work, an end surface, and a corner part can be made into the integrated state. By integrating the weld beads, the weld bead shape extending along the planned welding line can be formed uniformly, and the strength and aesthetic appearance of the welded portion can be sufficiently secured.

  Moreover, the 1st-3rd weld bead formation process is implemented in this order, and a 1st weld bead and a 2nd weld bead are connected by the 3rd weld bead formed at the 3rd weld bead formation process. May be. In the first weld bead formation process, it is necessary to irradiate the corners with laser light, and thus the stability of laser light scanning is an issue. In contrast, when the second and third weld bead forming steps are performed after the first weld bead forming step, dents or the like due to laser light occur in other portions in the first weld bead forming step. However, it becomes possible to repair a dent etc. with the 2nd and 3rd weld bead formed later.

  Further, in the first to third weld bead forming steps, the first to third weld beads may be formed by connecting a plurality of spot-like weld beads. In this case, the amount of heat input to the workpiece can be suppressed as compared with the case where continuous welding is performed. In addition, the width of the weld bead can be increased compared to the case where continuous welding is performed. Therefore, the first to third weld beads can be easily connected.

  Moreover, you may make the nugget diameter of a 2nd weld bead smaller than the nugget diameter of a 1st weld bead and a 3rd weld bead. Thereby, it becomes possible to connect the 1st-3rd weld bead smoothly.

  Further, in the third weld bead forming step, the third weld beads may be formed in a plurality of rows. Thereby, connection of the 1st-3rd welding bead becomes easy.

  In forming the first to third weld beads, the workpiece may be irradiated with laser using a contact tip. By using a contact chip, the stability of laser beam scanning can be improved.

  Further, the weld joint according to one aspect of the present invention is fillet welded to the end surface of one workpiece and the one surface of the other workpiece along a planned welding line set in an overlapping portion of the plate-like workpieces. The fillet weld portion is a first weld formed along a planned welding line at a corner portion formed by an end surface of one workpiece and one surface of the other workpiece. A bead and a second weld bead formed along a planned welding line at a corner located on the opposite side to the corner of the corner constituting the end surface of one workpiece, and welded to the end surface of the one workpiece A third weld bead formed along a predetermined line, and the first to third weld beads are connected to each other.

  In this weld joint, the first to third weld beads constituting the fillet weld are connected to each other. Thereby, the welding bead formed over the corner | angular part of a workpiece | work, an end surface, and a corner part can be made into the integrated state. By integrating the weld beads, the weld bead shape extending along the planned welding line can be formed uniformly, and the strength and aesthetic appearance of the welded portion can be sufficiently secured.

  Each of the first to third weld beads may be configured by connecting a plurality of spot-like weld beads. In this case, the amount of heat input to the workpiece can be suppressed as compared with the case where continuous welding is performed. In addition, the width of the weld bead can be increased compared to the case where continuous welding is performed. Therefore, the first to third weld beads can be easily connected.

  Further, the nugget diameter of the second weld bead may be smaller than the nugget diameters of the first weld bead and the third weld bead. Thereby, it becomes possible to connect the 1st-3rd weld bead smoothly.

  The third weld bead may be formed in a plurality of rows. Thereby, connection of the 1st-3rd welding bead becomes easy.

  According to the present invention, a weld bead shape can be formed uniformly in fillet welding.

It is a schematic sectional drawing which shows an example of the welded joint manufactured by applying one Embodiment of the laser welding method. It is the schematic which shows a fillet weld part. It is a flowchart which shows one Embodiment of the laser welding method. It is a schematic sectional drawing which shows a 1st weld bead formation process. It is a schematic sectional drawing which shows a 2nd weld bead formation process. It is a schematic sectional drawing which shows a 3rd weld bead formation process.

  Hereinafter, preferred embodiments of a laser welding method according to one aspect of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing an example of a welded joint manufactured by applying an embodiment of a laser welding method. A welded joint 1 illustrated in the figure is a joined body of an outer plate (one work) 2 and an entrance / exit frame (the other work) 3 used in a railway vehicle structure.

  The outer plate 2 is a flat plate member that forms the outer portion of the side structure of the railway vehicle. The outer plate 2 is made of, for example, stainless steel having a thickness of about 1.0 mm to 3.0 mm. In FIG. 1, the outer plate 2 has the same thickness as the entrance / exit frame 3, but the thickness relationship is not particularly limited. The outer plate 2 may be a plate-like member thinner than the entrance / exit frame 3.

  The entrance / exit frame 3 is a frame member that forms a door arrangement space provided in a side structure of the railway vehicle. The entrance / exit frame 3 is made of, for example, stainless steel having a thickness of about 1.0 mm to 6.0 mm. One end side of the entrance / exit frame 3 is a flat portion 4, and the other end side is a bent portion 5 that bends at a substantially right angle from the flat portion 4.

  The welded joint 1 is applied to a railway vehicle structure so that the bending direction of the bent portion 5 faces the vehicle interior side. In the present embodiment, the end portion 6 of the outer plate 2 is overlapped with the vehicle outer surface (one surface of the other workpiece) 4 a of the flat portion 4 in the entrance / exit frame 3. Fillet welding by laser welding is applied to the end surface 6a (the end surface of one workpiece) 6a of the outer plate 2 and the vehicle outer surface 4a of the entrance / exit frame 3, and the overlapping portion P is extended. A fillet weld W is formed along the direction (the depth direction in FIG. 1). By forming the fillet welded portion W, the entrance / exit frame 3 is firmly and watertightly joined to the outer plate 2.

  FIG. 2 is a schematic view showing the fillet weld W. In the figure, for convenience of explanation, the vehicle outer side surface 6b of the end portion 6 of the outer plate 2, the end surface 6a of the outer plate 2, and the vehicle outer side surface 4a of the entrance / exit frame 3 are shown in a plan view. As shown in FIG. 2, the fillet weld W is formed along a planned welding line L set at the overlapping portion P of the outer plate 2 and the entrance / exit frame 3. The fillet weld W has a first weld bead B1, a second weld bead B2, and a third weld bead B3, and these first to third weld beads B1 to B3 are connected to each other. It is configured by

  More specifically, the first weld bead B1 is formed along the planned welding line L at the corner 11 formed by the end surface 6a of the outer plate 2 and the vehicle outer surface 4a of the entrance / exit frame 3. The second weld bead B <b> 2 is formed along the planned welding line L at the corner portion 12 located on the opposite side of the corner portion 11 among the corner portions constituting the end surface 6 a of the outer plate 2. The third weld bead B3 is formed on the end surface 6a of the outer plate 2 along the planned welding line L.

  These first to third weld beads B1 to B3 are each configured by connecting a plurality of spot-like weld beads B to each other. Each weld bead B has, for example, an elliptical shape having a major axis in the direction of the planned welding line L. There is no particular limitation on the overlapping state of the adjacent weld beads B and B, and the weld beads B and B may overlap to the extent that they are in contact with each other. The beads B and B may overlap.

  In the present embodiment, the first weld beads B <b> 1 are formed in a row at the corner 11, and the second weld beads B <b> 2 are formed in a row at the corner 12. On the other hand, the third weld beads B3 are formed in two rows on the end surface 6a. Further, the nugget diameter R2 of each weld bead B in the second weld bead B2 is equal to the nugget diameter R1 of each weld bead B in the first weld bead B1 and the nugget diameter R3 of each weld bead B in the third weld bead B3. Is smaller than The nugget diameter R1 of each weld bead B in the first weld bead B1 and the nugget diameter R3 of each weld bead B of the third weld bead B3 are substantially the same diameter.

  Next, the laser welding method for forming the fillet weld W described above will be described in detail.

  FIG. 3 is a flowchart showing an embodiment of the laser welding method. As shown in the figure, this laser welding method includes a first weld bead forming step (step S01), a second weld bead forming step (step S02), and a third weld bead forming step (step S03). And is configured.

  The first weld bead forming step is a step of forming the first weld bead B1 along the planned welding line L at the corner 11 formed by the end surface 6a of the outer plate 2 and the vehicle outer surface 4a of the entrance / exit frame 3. It is. In the second weld bead formation step, the second weld bead B2 is applied along the planned welding line L to the corner portion 12 located on the opposite side of the corner portion 11 among the corner portions constituting the end surface 6a of the outer plate 2. It is a process of forming. The third weld bead forming step is a step of forming the third weld bead B3 along the planned welding line L on the end surface 6a of the outer plate 2.

  In carrying out laser welding in each process, for example, a hand torch type laser welding apparatus is used. The laser welding apparatus is an apparatus that emits laser light from, for example, a fiber laser oscillator from a torch part. Further, a contact chip for assisting manual scanning of laser light can be attached to the torch part.

  The contact tip is a hollow cylindrical member made of metal, for example, and the contact tip is provided with a plurality of contact surfaces that contact the workpiece by cutting out the peripheral surface of the cylindrical portion. It has been. The conductive material forming the contact chip is preferably a material having a hardness lower than that of the workpiece forming material from the viewpoint of preventing the workpiece from being damaged. For example, when the workpiece is a stainless steel plate, examples of the conductive material forming the contact chip include copper, a copper alloy, and conductive carbon.

  In the first weld bead forming step, the first contact tip 21 is used as shown in FIG. The convex tip of the first contact chip 21 has an exposed surface 23 and a first contact surface 24 located on one side of the central axis when viewed from the radial direction of the cylindrical portion 22 and the other of the central axes. A second contact surface 25 located on the side is provided. A corner 27 formed by the first contact surface 24 and the second contact surface 25 is a right angle and coincides with the central axis when viewed from the radial direction of the cylindrical portion 22. The exposed surface 23 is a surface for exposing the internal space of the cylindrical portion 22. Slag generated from the workpiece during welding is discharged from the exposed surface 23 to the outside.

  In the first weld bead forming step, the first contact surface 24 is brought into contact with the end surface 6 a of the outer plate 2, and the second contact surface 25 is brought into contact with the vehicle outer surface 4 a of the entrance / exit frame 3. In this state, when the laser light K is emitted so as to coincide with the central axis of the first contact chip 21, the laser light K is irradiated to the corner 11, and a spot-like weld bead B is formed at the corner 11. The Thereafter, the position of the torch portion T is scanned along the planned welding line L, and the spot-shaped welding beads B are sequentially formed, whereby the first welding bead B1 is formed along the planned welding line L. 2 and the entrance / exit frame 3 are joined.

  In the second weld bead forming step, the second contact tip 31 is used as shown in FIG. The concave tip portion of the second contact chip 31 has an exposed surface 33 and a first contact surface 34 located on one side of the central axis when viewed from the radial direction of the cylindrical portion 32, and the other side of the central axis. And a second abutting surface 35 located on the surface. The angle formed by the first contact surface 34 and the second contact surface 35 is a right angle.

  In the second weld bead forming step, the first contact surface 34 is brought into contact with the vehicle outer surface 6 b of the outer plate 2, and the second contact surface 35 is brought into contact with the end surface 6 a of the outer plate 2. In this state, when the laser beam K is emitted so as to coincide with the central axis of the second contact chip 31, the laser beam K is applied to the corner 12 of the outer plate 2, and the spot-like weld bead is applied to the corner 12. B is formed. Thereafter, the position of the torch portion T is scanned along the planned welding line L, and the spot-shaped welding beads B are sequentially formed, whereby the second welding bead B2 is formed along the planned welding line L, and the outer plate Two corners 12 are chamfered.

  In the third weld bead forming step, a third contact tip 41 is used as shown in FIG. The convex tip of the third contact chip 41 has an exposed surface 43 and a first contact surface 44 located on one side of the central axis when viewed from the radial direction of the cylindrical portion 42, and the other of the central axes. A second contact surface 45 and a third contact surface 46 located on the side are provided. In the third weld bead forming step, the first contact surface 44 is brought into contact with the end surface 6a of the outer plate 2, and the corner portion 47 formed by the second contact surface 45 and the third contact surface 46 is formed in the entrance / exit frame. 3 is brought into contact with the vehicle outer surface 4a. In this state, when the laser beam K is emitted so as to coincide with the central axis of the first contact chip 21, the laser beam K is irradiated onto the end surface 6a of the outer plate 2, and the spot-like weld beads B are formed on the end surface 6a. It is formed.

  Thereafter, the position of the torch portion T is scanned along the planned welding line L, and the spot-like welding beads B are sequentially formed, whereby the third welding bead B3 is formed along the planned welding line L. The second end face 6a is surface-treated. In addition, by forming the third weld bead B3, the first weld bead B1 and the second weld bead B2 formed earlier are connected to each other by the third weld bead B3.

  As shown in FIG. 2, when the third weld beads B3 are formed in a plurality of rows, the angle of the third contact tip 41 is changed so that the laser beam K is irradiated to different positions on the end face 6a. The torch portion T may be scanned after adjustment. In this case, the order of forming the plurality of rows of third weld beads B3 may be an arbitrary order.

  As described above, in this laser welding method, the first to third weld beads B1 to B3 formed in the first to third weld bead forming steps are connected to each other. Thereby, the welding bead B formed over the corner | angular part 12 of the outer plate 2, the end surface 6a of the outer plate 2, and the corner | angular part 11 which the outer plate 2 and the entrance / exit frame 3 make can be made into the integrated state. By integrating the weld bead B, the weld bead shape extending along the planned welding line L can be formed uniformly, and the strength and aesthetics of the fillet weld W can be sufficiently secured.

  In the present embodiment, the first to third weld bead forming steps are performed in this order, and the first weld bead B1 and the second weld bead B3 are formed by the third weld bead forming step. The weld bead B2 is connected. In the first weld bead forming step, the corner 11 needs to be irradiated with the laser beam K, and thus the scanning stability of the laser beam K is an issue. In contrast, by performing the second and third weld bead forming steps after the first weld bead forming step, other parts (for example, the corner portion 12 and the end surface 6a) are formed in the first weld bead forming step. Even when a dent or the like due to the laser beam K occurs, the dent or the like can be repaired by the second and third weld beads B2 and B3 to be formed later.

  In the present embodiment, the first to third weld beads B1 to B3 are formed by connecting a plurality of spot-like weld beads B in the first to third weld bead forming steps. Thereby, compared with the case where continuous welding is performed, the amount of heat input to the workpiece can be suppressed. In addition, the width of the weld bead B (the nugget diameter in the short axis direction in the example of FIG. 2) can be increased as compared with the case where continuous welding is performed. Accordingly, the first to third weld beads B1 to B3 can be easily connected.

  In the present embodiment, the nugget diameter R2 of the second weld bead B2 is smaller than the nugget diameter R1 of the first weld bead B1 and the nugget diameter R3 of the third weld bead B3. Thereby, it becomes possible to connect 1st-3rd welding beads B1-B3 smoothly. Further, the chamfered finish of the corner portion 12 of the outer plate 2 by the second weld bead B2 becomes good.

  In the present embodiment, in the third weld bead forming step, the third weld beads B3 are formed in a plurality of rows. Thereby, connection of 1st-3rd welding beads B1-B3 becomes easy.

  In the present embodiment, in the first to third weld bead forming steps, the workpiece is irradiated with laser using the first to third contact chips 21, 31, 41. By using the first to third contact tips 21, 31, 41 having different shapes for each of the first to third weld bead forming steps, it is possible to improve the scanning stability of the laser beam K.

  In the above-described embodiment, laser welding is performed in the order of the first weld bead formation step, the second weld bead formation step, and the third weld bead formation step, but these steps are performed in an arbitrary order. May be implemented. Moreover, in the said embodiment, although 3rd weld bead B3 is formed in several rows in the 3rd weld bead formation process, you may form 3rd weld bead B3 in 1 row.

  DESCRIPTION OF SYMBOLS 1 ... Welded joint, 2 ... Outer plate (one workpiece | work), 3 ... Entrance / exit frame (other workpiece | work), L ... Welding line, P ... Overlapping part, 4a ... Vehicle outer side surface (one side), 6a ... End surface , 11 ... corner, 12 ... corner, 21 ... first contact tip (contact tip), 31 ... second contact tip (contact tip), 41 ... third contact tip (contact tip), B ... welding Bead, B1 ... first weld bead, B2 ... second weld bead, B3 ... third weld bead.

Claims (10)

A laser welding method of performing fillet welding of an end surface of one workpiece and one surface of the other workpiece along a planned welding line set in an overlapping portion between plate-like workpieces,
A first weld bead forming step of forming a first weld bead along the planned welding line at a corner formed by an end surface of the one workpiece and one surface of the other workpiece;
A second weld bead forming step of forming a second weld bead along the planned welding line at a corner located on the side opposite to the corner among the corners constituting the end surface of the one workpiece;
A third weld bead forming step of forming a third weld bead on the end surface of the one workpiece along the planned welding line,
A laser welding method for connecting the first to third weld beads formed in the first to third weld bead forming steps to each other.   The first to third weld bead forming steps are performed in this order, and the first weld bead and the second weld bead are formed by the third weld bead formed in the third weld bead forming step. The laser welding method according to claim 1, wherein:   The laser welding method according to claim 1 or 2, wherein, in the first to third weld bead forming steps, the first to third weld beads are formed by connecting a plurality of spot-like weld beads.   The laser welding method according to claim 3, wherein the nugget diameter of the second weld bead is made smaller than the nugget diameters of the first weld bead and the third weld bead.   The laser welding method according to any one of claims 1 to 4, wherein in the third welding bead forming step, the third welding beads are formed in a plurality of rows.   The laser welding method according to claim 1, wherein, in forming the first to third weld beads, laser irradiation is performed on the workpiece using a contact tip. A weld joint in which fillet welds are provided on the end surface of one workpiece and one surface of the other workpiece, along a planned welding line set in an overlapping portion between plate-like workpieces,
The fillet weld is
A first weld bead formed along the planned welding line at a corner formed by the end surface of the one workpiece and the one surface of the other workpiece;
A second weld bead formed along the planned welding line at a corner located on the opposite side of the corner among the corners constituting the end surface of the one workpiece;
A third weld bead formed on the end surface of the one workpiece along the planned welding line;
A weld joint in which the first to third weld beads are connected to each other.   The weld joint according to claim 7, wherein each of the first to third weld beads is configured by connecting a plurality of spot-like weld beads.   The weld joint according to claim 7 or 8, wherein a nugget diameter of the second weld bead is smaller than a nugget diameter of the first weld bead and the third weld bead.   The weld joint according to any one of claims 7 to 9, wherein the third weld beads are formed in a plurality of rows.

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